Many mobile devices, such as for example a mobile phone, a personal digital assistant (PDA), a smart-phone, a lap-top computer, and a wrist-top device, contain and/or are connected to sensors that may be configured to provide real-time sensing data on the surrounding environment and/or the user of the mobile device. Based on the collected sensing data it is possible to deduce the current context, i.e. the state of the physical environment, the state of the mobile device itself, and/or the physiological state of the user, for example. The information about the context and changes in the context can be utilized in implementing context-aware applications such as for example context-sensitive user interfaces of mobile devices.
The challenges in implementing the context-aware applications are two-fold. Firstly, the changes of context should be recognized in a manner that the recognized context corresponds sufficiently well to the real-life situation concerning e.g. the state of the physical environment, the state of the mobile device itself, and/or the physiological state of the user. Publication Fl20095570 discloses an adaptive context recognition algorithm which may be initially trained by e.g. supervised adaptation process on the basis of available sensing data vs. indicated context information. The information needed for the supervised adaptation process may be, for example, data collected from a plurality of different users and it may thus provide a generally applicable initial state of the algorithm. After the initial adaptation process described above the algorithm may work reasonably well on average. Thereafter, on-line/run-time adaptation may take place upon receiving feedback by the user of the mobile device. The second challenge in implementing the context-aware applications relates to using the information provided by the context recognition for controlling the mobile device in such a manner that the service actions taken as a response to a recognized change of context correspond sufficiently well to the needs of the user. The service actions are related to services provided with the mobile device and they can be, for example, adaptation of the user interface of the mobile device, adaptation of an application, adaptation of a menu, adaptation of a profile, adaptation of a mode, trigger an application, and/or close an application. Publication US2002167488 discloses a mobile device that includes at least one sensor, such as a tilt sensor implemented by an accelerometer, which provides contextual information, e.g. whether the mobile device is being held or not. When the mobile device receives an incoming message, or notification, the device responds thereto based at least in part upon the contextual information. The control of the mobile device may work reasonably well on average when a sufficiently big group of users is under inspection but, in conjunction with a single user, the operation may, in some situations, be unsatisfactory.